Symmetrical and unsymmetrical tetranuclear cyanine dyes and process of preparing thesame



Patented Aug. 15 1950 UNITED STATES PATENT 2,518,731 OFFICE 2,518,731SYMMETRIGAL, AND. UNSYMMETRICAL TETRANUCLEAR CYANINIEI DYES AND PROGESSGF PREPARING THE SAME Thomas in. Thomson, Bing'hainton, N. Y.-, as-

signor to, General Aniline. & Film Corporation, New York, NLY acorporation of Delaware N6 nae-mi; Application December 21, 1948, 7senai No. 66,575

I This invention relates to tetranuclearcyanihe dyes n particularly i9vunsy ri a .ieiif ni r clear cyanine dyes and to a me, od oip epg n boththe symmetrical and unsymmetrical tetra nuclear cyanine dyes.,, 1Symmetrical tetr arge; haveb'een brepared: by the metho u crib'ed in teastates r nts. 2 ,3S,96T3, 3,39 ,s .9, and 2,430,295,211'1d. in

3''- olaims. (01. 260- 2401) fusing the intermediate with, methylp-toluene sulfiinate for '2 Zq-ho1ijrsat 160 ,Twof mole, of theresulting con est d are he ed in the tires; (5, o if h hi6] or a acidto] about 45' minutes to obtain a sym'ihe rlcal tetra nuclear dye inwhich the two inner nuclei are bridged by a polymethine chain; lfheminimum time required; to prepare the final dye is approximately 7 hoursand 15 minutes, exclusive of the time required to cool the reactionmixture in various stages and purification of the dyestufi.

, The method described in. United States Patent 2,395,537!) consists of,fir t condensing 2 molecules are s h e thereof a lite ,oeyeuelietcifietnylenecompoun of the action mixture is then pouidifitoaiiadueous' in which the two inner nuclei are linked together by apolymethine bridge, obtained by recrystallization from alcohol. Theminimum time required for the latter two steps is approximately from 50minutes to 3 hours; exclusive of the time required to cool the reactionmixture and to recrystalliz'e the final dye. I

Theoretically, the dyes of the United States Patent 2,395,879, whichcontain two thi o groups could be alkylated in such manner that only onealky'lthi'o group would be formed. If this reaction could beaccomplished, then, further treatmerit with a quaternary cyclammoniumsalt con taining a reactive methyl group might lead to a trinuc'lear dyewhich could again be alkylated and condensed with a second and differentcyclammonium salt to produce an unsymmetrical tetra' nuclear dye. At thepresent time, there is no method known nor are the intermediatesavailable by which unsymmetrical tetranuclear cya nine dyes could beprepared. It is an object of the present invention to provide animproved method for the production of symmetrical tetranucle'ar cyaninedyes containing two rhodanine rings as the inner nuclei bridged by thepolyniethine chain.

A further object is to provide unsymmetrical tetranuclear cyani'ne dyesbridged by the foregoing chain and to a method of preparing the same;

Other objects and advantages will become apparent from the followingdescription.

I have found that both symmetrical and unsymmetrical tetranuclearcyanine dyes are readily prepared in excellent yield and in readilypurifiabl'e form by heating a thiazolone cyanine dye propyl, isopropyland the like, in the presence of,

a basic condensing agent such astrimethylamine, triethylamine, pyridine,methyl pyridine, ethyl pyridine, q-uinoline, potassium carbonate and thelike, on a steam bath or by heating the reaction mixture at reflux for aperiod of 5 to 2Q minutes.

The dyes obtained by the foregoing procedure are characterized by thefollowing general fer-= mulae:

3 wherein R represents hydrogen or an alkyl group, e. g., methyl, ethyl,propyl, or butyl, R being only alkyl when n represents 1, both Rzs beingthe same and representing an alkyl, allyl, aryl, or aralkyl group, e.g., methyl, ethyl, propyl, phenyl, naphthyl, tolyl, benzyl, phenethyl,and the like, R3 represents an aliphatic radical, aryl or aralkylradical, e. g., methyl, ethyl, propyl, butyl, hydroxyethyl, ethoxyethyl,phenyl, tolyl, naphthyl, benzyl, phenethyl, menaphthyl and the like, Rand R which may be alike or different represent an alkyl, allyl, aryl oraralkyl group as given for R2, R and R which may be alike or differentrepresent an aliphatic, aryl or aralkyl radical as given for Rs, 11represents a positive integer of from 1 to 3, X represents an acidradical, e. g., chloride, bromide, iodide or alkyl sulfate, alkylp-toluenesulfonate or perchlorate, Z, Z, and Z" represent the atomsnecessary to complete a heterocyclic nucleus of the type contained incyanine dyes, e. g., oxazoles, thiazoles, selenazoles, and theirpolycyclic homologues, such as those of the benzene, naphthalene, i. e.,naphthiazole and perinaphthiazole, acenapthene, and anthracene series,pyridine, and its polycyclic homologues, such as quinoline and andfi-naphthaquinolines, perinaphthiazoles, indolenines, diazines, such aspyrimidines and quinazolines, diazoles (e. g., thio-B- fi-diazole),oxazolines, pyrrolines, thiazolones and selenazolines (the polycycliccompounds of these series being substituted if desired in thecarbocyclic rings with one or more conventional groups, such as alkyl oraryl as below, amino, hydroxy, alkoxy, i. e., methoxy, ethoxy, etc., andmethylenedioxy groups, or by halogen atoms, i. e., chlorine, bromine,eta), both Zs being the same, Z and Z" being the same or differentdepending upon whether R and R are the same or different. In otherwords, Z and Z may be the same if R and R are different, However, if Rand R" are the same then Z and. Z" must be different.

The thiazolone dye intermediates utilized as the co-reactant with thethiazolone cyanine dye salts are characterized by the following generalformulae:

2 I l; X

wherein R2, R3, X and Z have the same values as above, R4 represents anaryl group of the V benzene and naphthalene series, such as phenyl,chlorophenyl, diphenyl, tolyl, or naphthyl, R5 represents eitherhydrogen or an acetyl group,

' Serial No. 66,571, filed on December 21, 1948, and- 4 R6 represents analkyl or aralkyl'grou'p, e. e., methyl, ethyl, propyl, isopropyl,benzyl, phenethyl, and the like, R7 represents an alkyl group, e. g.,methyl, ethyl, propyl, isopropyl, butyl, isobutyl, etc. and n representsa positive integer of from 1 to 3, and Y represents the atoms necessaryto complete a saturated heterocyclic nitrogenous nucleus, such as, forexample, piperidine, 8- or 'y-pipecoline, pyrrolidine, morpholine,tetrahydroquinoline, and the like.

The dyestuff intermediates illustrated by Formulae a and c are preparedaccording to the method described in my copending application theintermediates illustrated by the second formula b are prepared accordingto the method described in my copending application Serial No. 66,572,filed on December 21, 1948.

The dyestuff intermediates illustrated by For-- mula a are, in general,obtained by treating a diarylformamidine or its vinylog, such asp-anilinoacrolein anil hydrochloride or glutaconic aldehyde dianilhydrochloride, in the presence of an acid condensing agent such asacetic anhydride, or in the presence of a basic condensing agent such astriethylamine, or piperidine, with a thiazolone cyanine dye.

The dyestufi intermediates illustrated by Formula b are obtained bytreating a thiazolone cyanine dye with an aliphatic acid anhydride inthe presence of a mixture of pyridine and triethylamine followed bytreatment with, phosphorus pentasulfide to yield the thio derivativewhich is subsequently alkylated with an alkylating agent in the usualway to yield the thioether derivative.

The thiazolone cyanine dyes utilized in preparing the foregoingintermediates and which are condensed with the saidintermediates arecharacterized by the following general formula:

wherein R2, R3, X and Z have the same values as above, and are preparedaccording to the method described in my copending application Serial No.786,814, filed November 18, 1947. In general, the method consists ofcondensing a substituted thioamide with an a-halogen acetic acid. Thecompounds, in view of their ketomethylene configuration, undergoketo-enol tautomerism, i. e., the keto group enolizes to form a hydroxylgroup.

The following examples describe the preparation of some of thethiazolone cyanine dye intermediates illustrated by Formulae a and bwhich are utilized in the preparation of the tetranuclear cyanine dyes.Y

- A m'iitureot gramsoi:diphenylformamidlne, 5rgram's-oi thev thiazolone.cyanifie dyeof the fol: Iowingl structure:

and cc. of acetic anhydride was heated, at 140 C. for 30 minutes. Aftercooling, the product was precipitated with ether and purified bydissolving it in a small amount of methanol followed by precipitationwith ether. A, yield oi'5.9 grams of yellow-green crystals, having amelting point at 213-215 C. was obtained.

Example II C. it: j i 5- cm 0: Lou-c I A mixture of 75 cc. of pyridine,15 cc. of propicnic anhydride, 15 cc. of triethylamine, and 15 grams ofthe thiazolone cyanine dye of the following structure:

Example HI A mixtui'e of '75 ccof. pyridine, 10 cc. of propionicanhydride, 10 cc. of triethylamine, and 13 grams of the thiazolonecyanine dye ofthlefollowmg, structure iii.

was heatedwith stirring at 120 c. for 20 minutes.

During the course or 10 minutes, a; total of 10 grams of phosphoruspentasulfide' was-added in pcrtionsat 120 6. Afteran additional 10 minutes of stirring at 120 ('31, the mixture was poured into coldfwater andst-iired' until the first formedoil solidified; The crude product wasstirred with 360 cc. of 2,16%; aqueous solution of sodium 11y: droxideandpurified by boiling out with isopro= panol. There was obtained 10.2grams cfyellow powder which. decomposes at about 200 C.

A mixture of 93 grams of the yellow powder and 10 grams of methylp-toluenesulfonate was. fused at 95 C. for 1 hour. After cooling, the;product; was washed with ether and dissolved in; 1 0 cc. of warmacetone. The final product was: precipitated as the iodide by adding 25cc. of? methanol containing 20% sodium iodide. The; product was washedwith water and purified by boiling out with iscpropanol. A yield of 4.3grams; of a product melting at 225-228 C. was obtained.

Example IV CHasor A mixture of 15 cc.-of, pyridine, 2 cc. of propionicanhydride, 2 cc. of triethylamiiie, and 2.0 grams of the thiazolonecyanine dye of the following structure:

was heated at 120 C. for 3 minutes. There were then added =2; grams ofphosphorus pentasulfide and the mixture heated at 115 C. for 15 minutes.

A darktr-ed oil was precipitated by the addition of cc. ofwater andwashed with water by decantationl The product was fused with 3 cc. ofmethyl sulfate at 95 C. for 10 minutes to yield 4.5 grams of ayellow-orange solution which may be employed ln dye synthesis.

Example VI A mixture of 2.85 grams of glutaconaldehyde dianilhydrochloride, 4.3 grams of the compound of Example III, 1 cc. ofpiperidine and50 cc. of methanol was heated at reflux for 30 minutes Thereaction mixture was poured into 300 cc. of water containing 5 grams ofpotassium iodide. The precipitated product was filtered and boiled outwith isopropyl alcohol. A yield of 3.7 grams of a compound having amelting point of 195- 198? C. was obtained. A methanol solution of theproduct has an absorption maximum at 624 ma.

7 Example VII H2 olH5-s-( J=os A'mixture (ifgrams of the compound ofExample I, 20cc. of n-butyric anhydride, 100 cc. of pyridine and 20 cc.of triethylamine was heated and stirred at 120 C. for 20 minutes. Therewere then added 20 grams phosphorus pentasulfide and stirring at 120 0.continued for 20 minutes. The reaction mixture was poured into 700 cc.of cold water. The resulting brown precipitate was filtered off, washedwith water, and boiled out with 100 cc. of isopropyl alcohol. A yield of20.9 grams of the driedand purified product was obtained. The compoundis presumed to be an'inner salt characterized by the followin formula;

40 A mixture of 2 grams of the above material and 2 gramsof ethylp-toluenesulfonate was fused at C. for 30 minutes. The reaction mixturewas dissolved in 30 cc. of hot acetone, and 10 cc. of a 10% solution ofsodium iodide in acetone was added. After cooling, the crystals wereseparated and purified by boiling out with isopropyl alcohol. A yield of1 gram of a product melting between 2l0-213 C. was obtained.

The anions of the foregoing thiazolone cyanine dye salt intermediatesmay be replaced by other anions, such as iodide, thiocyanate, or"perchlorate, by treating an alcohol solution of the dye salt with anaqueous -or aqueous-alcohol solution containing a sodium or potassiumsalt of the desired'anions. r

The following examples describe in detail the method of preparing thesymmetrical and unsymmetrical tetranuclear cyanine dyes from theforegoing thiazolone cyanine dye salts and dye salt intermediates, butit is to be understood that theyv are given merely for the purpose ofillustra tion and are not to be construed as limitative.

A mixture of 0.3 gram of p-toluenesulfonate salt ofthe product ofExample III, 0.3 gram of the thiazolone cyanine dye utilized in ExampleIV, 15 cc. of methanol, and 0.5 cc. of triethylamine was heated atreflux for 15 minutes. 20 cc. of 20% sodium bromide in methanol wasadded and the dye separated on cooling and was purified boiling out withisopropyl alcohol. A yield of were heated at reflux for 5 minutes. Aftercooling, the dye crystals were removed and purified by boiling out withisopropyl alcohol. A yield of 0.25 gram of a product melting at 237239C. was obtained. A:methanol solution of the dye absorbs light with twomaxima at 420 in and 734 m The --sensi-tization of a photographicemulsion is extended to 800 m witha maximum 0.4 gram of a productmelting at 220-227 C. was at 760 m Example X] s SG-CH=OHDH=iOH-OH=GSs-oH acac O=i acacg l N/ \N CH:

.A mixture of 0.3 gram :of the vproduct of Examplell, 0.3 gram of thethiazolone cyanme dye utilized in Example III, '20 cc. of isopropylalcohol, and, 1 cc. of 'triethylamine was heated at reflux "for '10minutes. Two cc. of sodium iodide in methanol was added and the dyeseparated on cooling and was purified by boiling out with isopropylalcohol. =A yield of 025 gram of 'a product melting at "225-226" C. *wasobtained.

In methanol solution this dye absorbs with a maximum at 627 In 1.. Thedyesensitizes aphotographic emulsion with a maximum at 695 11151..

A mixture of 0.5 gram of the product of Ex-- ample 20 cc. of :methanol,0.5 cc. of triethylamine, and 0.4 gram of a thiazolone dye having thefollowing formula:

was heated at reflux for 5 minutes. After cooling, the reaction mixturewas poured into an aqueous solution of potassium iodide, the dye wasseparated and purified by boiling out with isopropyl alcohol. A .yieldo'f 0.4 gram of a product melting :at 2-1'42'18C. was obtained. Amethanol solution has absorption maxima at 447 and 811 m When the dye isincorporated in a photographic emulsion the sensitization "is extendedto 900 m with a maximum at 850 mp.

A mixture of 0.7 gram of the product of Example V'II and 2 cc. of methylsulfate was fused at 95 C. for 30 minutes. There were then added 25 cc.of isopropanol, 3 cc. of triethylamine, and

0.4 gram of a thiazolone cyanine dye having the following formula:

melting at 244-251 C. was obtained. A methanol solution of the dye hadan absorption maximum at 623 m When added to a photographicsilver-halide emulsion, the dye extends the range of sensitization to735 III/.L with a maximum at 700 mp.

Eazample XIII A mixture of 0.61 gram of the product of with methylalcohol. A yield of 0.6 gram of a product melting at 279-280 C. wasobtained. The absorption maxima of a methanol solution of the dye are at418 and 437 m Example XIV A mixture of 0.64 gram of the product ofExample VI, 0.43 gram of the thiazolone cyanine dye utilized in ExampleIII, 30 cc. of methanol and 0.5 cc. of triethylamine was heated atreflux for 15 minutes. The dye separated on pouring the reaction mixtureinto aqueous potassium iodide and purified by boiling out with methylalcohol. A yield of 0.6 gram of a product melting at 215-216 C.wasobtained. A methanol solution of the dye has one absorption maximumat 808 m and another of lesser intensity at It is evident from theforegoing examplesthat the procedure employedin the preparation of'tetranuclear cyanine dyes is simple and requires a shorter period oftimer By merely choosing from a wide variety of thiazolone cyanine dyeand dye intermediates, both symmetrical and unsymmetrical tetranuclearcyanine dyes are obtained in excellent yield and in readily purifiableform.

While I have disclosed the preferred embodiments of my invention and thepreferred modes Example V, 0.43 gram of the thiazolone cyanine 7 ofcarrying the same into effect, it will be readily dye utilized inExample III, 30 cc. of methanol and 0.5 cc. of triethylamine was heatedat reflux for 15minutes. After cooling, the mixture was poured into anaqueous solution of sodium iodide apparent to those skilled in the artthat many variations may be made therein without departing from thespirit thereof. Accordingly, the scope of my invention'is to be limitedsolely by and the precipitated dye purified by boiling out 75 theappended ai s- 13 1 1 I claim: a with athiazolone cyaninedye'intermediate char- 1. Unsym'metrical tetranuclear cyanine dyeaStufis having the general formula: v acterized by a formulaselected fromthe.v l ass z S.-VC=CR(GH =CH) -.C -S :05-91 =0 110-41 :011 k s 1 Nfill! 1 1L]! H l 7 7. m consisting of the following formulae: L whereinn represents a positive integer of from R6 1 to 3, R is selected fromthe class consisting of CE 1 hydrogen and alkyl, Rbeing only alkyl whenn /(E=QH-'-C: represents 1, R andR'fare selected iron; the Nclassconsisting :of a'lkyl, allyL aryl"andr aralkyl X groups, R' and R'are selected from the class v R1 consisting of lower alkyl, lowerihydroxyalkyl, V 1. ii i lower alkoxyalkyl, arylof'the'benzene-and naph-I" N :1 i thalene series, and aralkyl groups, X represents 1 1k i n X anacid radical, Z and Z" are the radicals of and v i 2 heterocyclic nucleiof the type eusedrin' cyanine ,CHa I dyes, and wherein at least one'o'f' the groups of f \YN (OH=OH)H CH=O S Z\ radicals RR" and z' z" aredissimilar. O: v J5=OH C '2. An unsymmetrlcal tetranuclearcyanme dye- 80N stuff having the formula: I it: it; x

erein n p e ents p it i e er from CH5 CH3 7 a CHr - s r V 21 3. Anunsymmetrical te'tranuclear cyanine dye- 1 to 3, R2 is selected from theclass consisting of stufi having the formula: i alkyl, allyl, aryl andaralkyl groups, R reprer CH3 S 02115 4. Anunsymmetrical tetranuclearcyanine dyesents a member selected from the class consiststuff havingthe formula: ing of lower alkyl, lower hydroxyalkyl, lower als J sSO=OHCH=CHO--S \C=CH(E =0 HO- =GH--O/ H on=cn 52H; a 1 5 5. A processfor the production of tetranuclear koxyalkyl, aryl of the benzene andnaphthalene cyanine dyestufis which comprises heating in series andaralkyl groups, R4 represents an aryl the presence of a basic condensingagent a thiagroup, R5 represents a member selected from the zolonecyanine dye of the general formula: 7 class consist ng of h d a d acetylr up, H20 3 R6 represents a member selected from the class I consistingof alkyl and aralkyl groups, R7 represents an alkyl group, X representsan acid radical, Y represents the atoms necessary to complete in its x asaturated nitrogenous heterocyclic ring system selected from'theclassconsisting of-piperidine, 5- and y-pipecoline, pyrrolidine,morpholine, and tetrahydroquinoline, Z and Z' are residues ofh-eterocyclic nuclei of the type used in cyanine dyes.

6. A process for the production of an unsymmetrical tetranucleardyestufi which comprises heating in the presence of a basic condensingagent a thiazolone cyanine dye havethe formula:

CH: H10 8 Ull 7 CH3 O= =CH- hHa with a thiazolone cyanine dyeintermediate having the formula:

CaHs

heating in the presence of a basic condensing agent a thiazolone cyaninedye having the for-i o=o o=oH-o mula:

16 with a thiazolone cyanine dye intermediate having the formula:

8. A process for the production of an unsymmetrical tetr-anucleardyestuff whichcomprises heating in the presence of a basic condensingagent a thiazolone cyanine dye having the formula: V-

s H'CS' on new 1 Hz.CH=CH2 2115 with a thiazolone cyanine dyeintermediate hav ing the .formula:

/CHa-CH2 on, V N-on on-omog-fs CHa-CH: O=

THOMAS R. THOMPSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Nurnber v Kendall Mar. 5, 1946

1. UNSYMMETRICAL TETRANUCLEAR CYANINE DYESTUFFS HAVING THE GENERALFORMULA: